CVE-2023-51540
📛 CVE Title
WordPress Custom 404 Pro Plugin <= 3.10.0 is vulnerable to Cross Site Scripting (XSS)
Description
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Kunal Nagar Custom 404 Pro allows Stored XSS.This issue affects Custom 404 Pro: from n/a through 3.10.0.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- Patchstack
- CVSS severity
- HIGH
- CVSS score
- 7.1 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L- Effective score
- 7.1 / 10 HIGH source: CNA overview
- CWE(s)
-
CWE-79 - Reserved
- 2023-12-20
- Published
- 2024-02-01 11:11 UTC
- Last updated
- 2026-04-28 18:09 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2023/51xxx/CVE-2023-51540.json
- Linked Threat
- CVE-2023-51540 — Custom 404 Pro <= 3.10.0 - Unauthenticated Stored Cross-Site Scripting via logging
NVD triage scoring NVD CVE 2.0
Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.
- NVD published
- 2024-02-01 11:15:10 UTC
- NVD last modified
- 2026-06-17 06:41:10 UTC
- NVD CVSS v3.1
- 7.1 / 10 HIGH source: audit@patchstack.com
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L- Exploitability subscore
- 2.8 / 10
- Impact subscore
- 3.7 / 10
- EPSS score
- 0.0035 (probability of exploitation in next 30 days)
- EPSS percentile
- 27.53% vs all CVEs — higher = more likely to be exploited, as of 2026-07-11
NVD / KEV / EPSS data refreshed 2026-07-11 22:11 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
European Union Vulnerability Database ENISA EUVD
ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.
- EUVD ID
-
EUVD-2023-56252 - Assigner
- Patchstack
- Published
- Feb 1, 2024, 10:11:41 AM
- Updated
- Apr 28, 2026, 4:09:04 PM
- EUVD base score (CVSS 3.1)
-
7.1 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L - EUVD-reported EPSS
- 0.0800
- Vendors
- Kunal Nagar
- Products
-
Custom 404 ProCustom 404 Pro (n/a ≤3.10.0)
- Aliases
-
GHSA-77pp-vwgv-x2jq
ENISA description: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Kunal Nagar Custom 404 Pro allows Stored XSS.This issue affects Custom 404 Pro: from n/a through 3.10.0.
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Kunal Nagar | Custom 404 Pro |
n/a (affected)
|
— |
Affected products — CPE 2.3 (1) NVD
NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.
cpe:2.3:a:kunalnagar:custom_404_pro:*:*:*:*:*:wordpress:*:*
Vendor references (1)
References embedded in the original CVE record by the assigning CNA.
MITRE references (1) cveawg.mitre.org
Pulled from MITRE's CVE Services API by the 🛰 Backfill from MITRE button.
Web references (5)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- http://cwe.mitre.org/data/definitions/79.html rapid7:cwe.mitre.org
- https://attackerkb.com/topics/CVE-2023-51540 rapid7:attackerkb.com
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2023-56252 rapid7:euvd.enisa.europa.eu
- https://www.cve.org/CVERecord?id=CVE-2023-51540 rapid7:www.cve.org
- https://www.wordfence.com/threat-intel/vulnerabilities/id/1106e7b2-eac7-459d-8eb3-fe84c76f3b67?source=api-prod rapid7:www.wordfence.com
NVD-tagged references (2)
Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.
- https://patchstack.com/database/vulnerability/custom-404-pro/wordpress-custom-404-pro-plugin-3-10-0-cross-site-scripting-xss-vulnerability?_s_id=cve audit@patchstack.com Third Party Advisory
- https://patchstack.com/database/vulnerability/custom-404-pro/wordpress-custom-404-pro-plugin-3-10-0-cross-site-scripting-xss-vulnerability?_s_id=cve af854a3a-2127-422b-91ae-364da2661108 Third Party Advisory
Indicators (2)
IOCs linked to the auto-promoted Threat row.
| Type | Value | VirusTotal | Attached |
|---|---|---|---|
| domain |
xss.this
|
no local data | 2026-05-18 21:20 UTC |
| cve |
CVE-2023-51540
|
no local data | 2026-06-06 14:49 UTC |
Remediations (21)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:www.crowdstrike.com
Microsoft has released security updates for 63 vulnerabilities, including 1 zero-day and 4 critical vulnerabilities, in its November 2025 Patch Tuesday rollout.
2026-06-30 19:57 UTC -
web:blog.qualys.com
With Qualys Policy Audit's out-of-the-box mitigation or Compensatory Controls, which reduce the risk of a vulnerability being exploited because the remediation ( fix / patch ) cannot be done immediately, these security controls are not recommended by any industry standards, such as CIS and DISA-STIG.
2026-06-30 19:57 UTC -
web:www.oracle.com
This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.
2026-06-30 19:57 UTC -
web:www.microsoft.com
Security Update Guide Notifications Microsoft's free Security Update Guide Notifications provide links to security-related software updates and notification of re-released security updates. These notifications are sent via email throughout the month as needed.
2026-06-30 19:57 UTC -
web:nvd.nist.gov
The NVD is the U.S. government repository of standards based vulnerability management data represented using the Security Content Automation Protocol (SCAP). This data enables automation of vulnerability management, security measurement, and compliance. The NVD includes databases of security checklist references, security-related software flaws, product names, and impact metrics. For ...
2026-06-30 19:57 UTC -
web:www.lansweeper.com
Which vulnerabilities, issues, and other things did Microsoft update? Discover what's new using Lansweeper's Patch Tuesday November 2025 summary.
2026-06-30 19:57 UTC -
Wordfence remediation: Custom 404 ProWordfence
Update to version 3.10.1, or a newer patched version
2026-06-06 14:49 UTC -
web:www.computerworld.com
Each month, the team at Readiness analyzes the latest Patch Tuesday updates from Microsoft and provides detailed, actionable testing guidance. The company's Patch Tuesday release for February ...
2026-05-22 07:49 UTC -
web:www.notebookcheck.net
Microsoft confirmed that its April 2026 security updates, including KB5082063 and KB5083769, are triggering BitLocker recovery prompts on some Windows Server 2025, Windows 11, and Windows 10 devices.
2026-05-22 07:49 UTC -
web:www.helpnetsecurity.com
Microsoft is working on a fix for CVE -2026-45585 (aka "Yellowkey"), a vulnerability that can be used to bypass Windows' BitLocker protection.
2026-05-22 07:49 UTC -
web:nvd.nist.gov
Vulnerabilities All vulnerabilities in the NVD have been assigned a CVE identifier and thus, abide by the definition below. CVE defines a vulnerability as: "A weakness in the computational logic (e.g., code) found in software and hardware components that, when exploited, results in a negative impact to confidentiality, integrity, or availability. Mitigation of the vulnerabilities in this ...
2026-05-22 07:49 UTC -
web:federalnewsnetwork.com
CISA this year has already started accelerating the deadlines for agencies to patch software bugs posted to the Known Exploited Vulnerabilities (KEV) catalog.
2026-05-22 03:59 UTC -
web:www.secure.com
Learn the difference between vulnerability remediation and mitigation , and how a risk-based strategy can strengthen your security posture.
2026-05-22 03:59 UTC -
web:www.securityweek.com
Microsoft has announced mitigations for CVE -2026-45585, a BitLocker bypass triggered via FsTx in Windows Recovery.
2026-05-22 03:59 UTC -
web:www.techrepublic.com
Microsoft's April 2026 Patch Tuesday fixes 165 vulnerabilities, including two zero-days, in one of the company's largest monthly security updates.
2026-05-22 03:59 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-05-22 03:59 UTC -
web:translate.google.com
Google's service, offered free of charge, instantly translates words, phrases, and web pages between English and over 100 other languages.
2026-05-22 03:59 UTC -
web:cybersecuritynews.com
No patch has been released yet; Microsoft has instead issued a multi-step manual mitigation guide while a formal security update is prepared. Windows BitLocker Security Bypass The vulnerability originates in WinRE's handling of the BootExecute registry value under HKLM\ControlSet001\Control\Session Manager.
2026-05-22 03:59 UTC -
web:portal.msrc.microsoft.com
The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.
2026-05-22 03:59 UTC -
web:www.cve.org
At cve .org, we provide the authoritative reference method for publicly known information-security vulnerabilities and exposures
2026-05-22 03:59 UTC -
web:krebsonsecurity.com
October's Patch Tuesday also marks the final month that Microsoft will ship security updates for Windows 10 systems.
2026-05-22 03:59 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2023-51540.json.
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